The present invention relates to a new and improved anaerobic bioremediation system and method thereof for anaerobic biodegradation, detoxification and transformation of toxic organic and inorganic compounds in contaminated geologic formations to harmless and safe organic and inorganic materials within the geologic media. More particularly, the bioremediation system includes a chemical composition and apparatus for implementing the conversion of contaminated organic and inorganic materials to clean, safe, and harmless materials via naturally occurring anaerobic bioremediation within the geologic media.
Aerobic and anaerobic bioremediation of contaminated soils, ground water sites, lakes, ponds, aquifers, wells, shore fronts, oceans and the like have proven effective in remediating toxic organic and inorganic compounds such as fuel oil, gasoline, PCBs, DDT, and other pesticides, and the like. Bioremediation projects that have been successfully implemented are in areas that include underground storage tank spills and leakages; hazardous solid wastes; ground spills; and contamination of-ground water (wells), geological aquifers and the like. Aerobic and anaerobic bioremediation have proven to be more cost effective and timely than conventional engineering technologies, and have the further advantage in that they do not produce wastes which enter the surrounding air, water and soils. Anaerobic bioremediation has been shown to be the most effective and least expensive method of remediation of toxic materials. Other remediation technologies such as standard physical soil and ground-water remediation ie. excavation and disposal or pump and treat systems and soil-vapor extraction (SVE) remediation which have all been shown to be moderately high in capital costs; require long-term operation and maintenance including labor, materials and power consumption; time parameters that are in months to years; and remediation effectiveness results being moderately low in the cleaning-up of the contaminated soils and ground water. These remediation techniques are also limited by considerations of depth of soil to be removed; obstructions in the geologic formations; safety conditions at the site; and environmental law statutes with regard to Federal, State and local regulatory agencies for a site remediation project that produces wastes that effect air, water and soil conditions. These aforementioned remediation technologies generally are less feasible, and significantly more expensive and sometimes prohibitive in terms of logistics and/or overall costs.
Problems associated with anaerobic bioremediation have included the difficulty of achieving significant increases in the naturally occurring indigenous microorganisms at the contaminated site using appropriate chemical compositions of nutrients that would successfully have the indigenous anaerobic bacteria metabolize the organic and inorganic contaminants. The inability to maximize the rate of metabolism of toxic contaminants by anaerobic microorganisms can be due to inadequate or incorrect electron acceptors, nutrient forms of nitrogen and phosphorus, trace-mineral micronutrients, chelating agents, non-toxic surfactants, lack of carbon co-substrates, and inerting agents. There is also a physical inability to deliver, distribute and disperse the nutrients readily, rapidly and over a wide distribution area within the contaminated geologic media for effective biodegradation of the contaminated substances into non-toxic end-products. Also, there is a difficulty of working with anaerobic microorganisms and processes because the biochemical pathways describing the anaerobic degradation of organic and inorganic compounds have been difficult to characterize, and to a large degree, are yet to be fully understood. Thus, it can be seen that anaerobic bioremediation of contaminated geologic media such as ground water (wells), sludge, soil and the like is not an easy or simple technological problem.
There remains a need for an improved method and apparatus for the anaerobic bioremediation of organic and inorganic toxic compounds within a contaminated geologic media to form non-toxic end products without further formation of waste by-products that effect air, water and soil qualities at the geologic site. In addition, there is a need that the bioremediation be accomplished by having an in-situ treatment of the contaminated geologic media such that the organic and inorganic contaminants are metabolized or transformed by naturally occurring indigenous, denitrifying and/or manganese-, iron- and sulfate-reducing anaerobic microorganisms using the aforementioned electron acceptors, in combination with nutrients, surfactants, chelating agents, a diluent, and an inert gas to convert the contaminants within the contaminated geologic media into non-toxic end products. These naturally occurring indigenous microorganisms which operate using one or more respiration pathways are hereafter called xe2x80x9cmultiple respiration pathwayxe2x80x9d (MRP) microorganisms.
Methods, apparatus and chemical compositions having nutrients for bioremediation using anaerobic microorganisms have been disclosed in the prior art. For example, U.S. Pat. No. 5,178,491 to Graves et al discloses a vapor-phase nutrient delivery system for in-situ bioremediation of soil. The nutrients are delivered in the vapor phase to the affected areas of the contaminated soil for utilization by microorganisms to promote the metabolism of organic contaminants by the microorganisms. The delivery system includes a series of pumps, nutrient tanks, conduits, and wells for implementing the bioremediation process. This prior art patent does not disclose the apparatus, process or chemical compositions for the bioremediation of contaminated geologic media as in the present invention.
U.S. Pat. No. 5,265,674 to Fredrickson et al discloses an enhancement method of in-situ remediation of aquifers. This method of bioremediation is adapted to deliver microorganisms, enzymes, nutrients and electron donors to subsurface zones contaminated by nitrates in order to stimulate or enhance denitrification. The remediation system includes nutrient tanks, rumps, conduit/piping, an injection well and reclamation tanks. This prior art patent does not disclose the apparatus, process or chemical compositions for the bioremediation of contaminated geologic media as in the present invention.
U.S. Pat. No. 5,342,769 to Hunter et al discloses a method for bioremediation of liquid or slurry hazardous waste streams for the removal of halogenated hydrocarbons by using naturally occurring anaerobic microorganisms having methanogenic characteristics. The remediation method includes a series of reactors, pumps, vacuum pumps, and conduits. This prior art patent does not disclose the apparatus, process or chemical compositions for the bioremediation of contaminated geologic media as in the present invention.
U.S. Pat. No. 5,384,048 to Hazen et al discloses an apparatus and method for in-situ bioremediation of contaminated ground water and/or contaminated subsurface soil by chlorinated hydrocarbons. A nutrient fluid is used to stimulate the growth and reproduction of indigenous aerobic microorganisms that are capable of degrading the contaminants. The apparatus used for the bioremediation process includes injection wells, pumps, conduits, and monitoring/sensor components. This prior art patent does not disclose the apparatus, process or chemical compositions for the bioremediation of contaminated geologic media as in the present invention.
U.S. Pat. No. 5,398,756 to Brodsky et al discloses a process for the in-situ bioremediation of contaminated soil. The process includes the forming of at least one liquid permeable region within the contaminated soil region, introducing microorganisms, nutrients and the like for degrading contaminants in the contaminated soil region, and transmitting direct electric current through the contaminated soil region for degrading the contaminants by electrochemical means. This prior art patent does not disclose the apparatus, process or chemical compositions for the bioremediation of contaminated geologic media as in the present invention.
U.S. Pat. Nos. 5,482,630 and 5,556,536 to Lee et al and Turk disclose a controlled denitrification process and system using a bacterial bed. This bioprocess system is used for the reduction of nitrate to nitrogen in a fluid medium, such that anaerobic bacteria fed by a carbon source are used for the nitrate reduction. A column of suspended beads are used as the anaerobic bacterial bed for denitrification. This prior art patent does not disclose the apparatus, process or chemical compositions for the bioremediation of contaminated geologic media as in the present invention.
U.S. Pat. No. 5,560,737 to Schuring et al discloses a method and apparatus for pneumatic fracturing and multicomponent injection enhancement of in-situ bioremediation in treating subsurface soil contaminated with organic compounds. This bioremediation method and apparatus provides for reducing or eliminating non-naturally occurring, subsurface, liquid contaminants within a geologic formation, which involves the steps of pneumatically fracturing the soil formation to produce a fracture network. A pressurized gas stream is used having nutrients, oxygen, electron acceptors, pH buffers, and possible bacterial augmentation to add a different culture of microorganisms to the soil formation when used in fracturing the soil formation. This provides the proper growth of the bioremediation microorganisms within the fracture network in which to degrade the contaminated materials within the water or soil formations. This prior art patent does not disclose the apparatus, process or chemical compositions for the bioremediation of contaminated geologic media as in the present invention.
None of the prior art patents teach or disclose the apparatus, process or chemical compositions for the bioremediation of contaminated geologic media as in the present invention. Also, none of the prior art patents teach or disclose the process or system of the current invention for the in-situ treatment of contaminated geologic media by using multiple-respiration pathway (MRP) anaerobic microorganisms such as denitrifying, manganese-, iron- and sulfate-reducing anaerobic microorganisms.
Accordingly, it is an object of the present invention to provide an anaerobic bioremediation system for the anaerobic biodegradation, detoxification and transformation of toxic organic and inorganic contaminants in contaminated geologic media into non-toxic compounds without further formation of regulated wastes or other undesirable by-products that effect the air, water and soil at environmental-contamination sites.
Another object of the present invention is to provide an anaerobic bioremediation system for in-situ treatment of geologic media containing organic and inorganic contaminants that are metabolizable or transformable by indigenous anaerobic bacteria capable of utilizing one or more multiple respiration pathways (MRP) including denitrification, manganese-reduction, iron-reduction and sulfate-reduction within the contaminated geologic media at a site.
Another object of the present invention is to provide an anaerobic bioremediation system having apparatus which enables the delivery of nutrients and electron acceptors having an inert carrier gas to the indigenous MRP anaerobic microorganisms in order to promote conditions favorable to the growth of these indigenous microorganisms such that the metabolism or transformation of the contaminants by these microorganisms can easily take place, without the use of implanted microorganisms at the contaminated site.
Another object of the present invention is to provide an anaerobic bioremediation system having apparatus which enables the nutrients and electron acceptors and an inert carrier gas to be more readily and rapidly dispersed in the contaminated geologic media and made more available to a large area within the contaminated geologic media.
Another object of the present invention is to provide an anaerobic bioremediation system having the nutrients, electron acceptors, chelating agents, surfactants and diluent with an inert carrier gas being in a chemical composition form that is readily utilizable and metabolizable by the indigenous MRP anaerobic microorganisms.
Another object of the present invention is to provide an anaerobic bioremediation system that has the capacity to supply macro-nutrients, micro-nutrients, electron acceptors, surfactants, and chelating agents, as well as to modify the pH, redox potential and oxygen availability in the subsurface geologic media.
Another object of the present invention is to provide an anaerobic bioremediation system that has the capacity to supply organically usable phosphate to phosphate-limited environments whereby sodium hexametaphosphate or other forms of hydrolyzable ringed or linear polyphosphates are used as the primary source of phosphate as such compounds are much less prone to in-situ precipitation than other forms of phosphate which enables a major improvement for the stimulation and growth of indigenous MRP microorganisms in the contaminated geologic formation.
Another object of the present invention is to provide an anaerobic bioremediation system that has the capacity to supply nitrate as both an electron acceptor and the main source of assimilated (i.e., nutrient) nitrogen, taken together with other unique aspects of the chemical compositions of the present invention, which enables a major improvement for the stimulation and growth of indigenous MRP microorganisms in the contaminated geologic media.
Another object of the present invention is to provide an anaerobic bioremediation system having apparatus that is simple to construct and use and which enables efficient delivery and monitoring of the nutrients and electron acceptors for the optimum growth rate and kinetics of various indigenous, denitrifying and other MRP anaerobic microorganisms in order to maximize the rate of degradation and transformation of the contaminants into non-toxic compounds by these indigenous MRP microorganisms.
Another object of the present invention is to provide an anaerobic bioremediation system having a process that is inexpensive and easy to operate, especially in the field on a large scale basis.
Another object of the present invention is to provide an anaerobic bioremediation system having a process that can be performed rapidly and safely in the field and result in the site meeting environmental clean-up standards set by various governmental agencies more rapidly and at a lower cost than can be accomplished with other methods.
A further object of the present invention is to provide an improved anaerobic bioremediation system that can be easily produced in an automated and economical manner and is readily affordable by various responsible parties, consultants, contractors, engineers, governmental agencies and corporate users.
In accordance with the present invention there are provided liquid chemical compositions for anaerobic biodegradation, detoxification, and transformation of toxic organic and inorganic compounds in a contaminated geologic media under reducing conditions, including, but not limited to, denitrifying, manganese-reducing, iron-reducing and sulfate-reducing conditions. One such liquid chemical composition includes sodium nitrate in the range of one-fifth (0.2) to four (4) pounds per gallon of the chemical composition; sodium hexametaphosphate or other biologically hydrolyzable ring or linear polyphosphate in the range of one twentieth (0.05) to five (5) pounds per gallon of the chemical composition; a surfactant in the range of 0.01% to 10% by volume of the chemical composition; and a diluent in the form of water.
The present invention further includes a bioremediation apparatus for anaerobic biodegradation, detoxification, and transformation of toxic organic and inorganic compounds in a contaminated geologic media. The bioremediation apparatus includes a first set of one or more storage tanks containing a chemical composition for anaerobic biodegradation of toxic compounds in contaminated geologic media; a plurality of quick disconnect valve couplings connected to the first set of storage tanks; at least one logic controller having a logic controller programmer component for opening and closing an automatic valve connected to the first set of storage tanks to supply the chemical composition to the contaminated geologic media; and a screened well connected to the first set of storage tanks for supplying the chemical composition to the contaminated geologic media.
The present invention also includes methods for anaerobic biodegradation, detoxification, and transformation of toxic organic and inorganic compounds in contaminated geologic media. The basic method includes pressurizing one or more storage tanks containing a chemical composition and an inert carrier gas; connecting a plurality of quick disconnect valve couplings to one or more pressurized storage tanks; connecting a well to an automatic ball valve for supplying the chemical composition and the inert carrier gas through the well to the contaminated geologic media; and opening and closing of the automatic ball valve to dispense the chemical composition and the inert carrier gas under pressure through the well to the contaminated geologic media. Methods are also disclosed for alternating the cycles of redox potential and the predominant microbial respiration pathway within the contaminated geological media.